Antero Resources Inc., an energy company backed by New York private-equity firms, plans to spend more than half a billion dollars on a pipeline. But the 80 miles of pipe won't transport oil or gas: They will carry water from the Ohio River to fracking sites in West Virginia and Ohio.

The project is a costly wager that the hydraulic-fracturing industry's thirst for reliable sources of water will grow over the next few years. Fracking, an oil-field technique driving the nation's current energy boom, involves injecting vast...